Compressor



H. H. BIXLER Nov. 7, 1933.

COMPRES SOR Filed March 1'7, 1933 Hamky H. Bi xlern His Abbowrngg.

Patented Nov. 7, 1933 PATENT OFFICE COMPRESSOR Harley E. Bixler, Schenectady, N. 2., assignor to General Electric Company, a corporation of New York Application March 17, 1933.

13 Claims. (01. 230-206} My invention relates to fluid compressors, such as used in refrigerating machines.

An object of my invention is to provide a fluid compressor and a lubricant pressure responsive unloading device therefor which device shall not require any moving valve parts.

Another object of my invention is to provide a fluid compressor of simplified construction having substantially no clearance loss.

Further objects and advantages of my invention will become apparent as the following description proceeds and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding .of my invention,

reference may be had to the accompa y n draw= ing in which Fig. 1 is an elevation partly in section ofv a refrigerating machine employing a compressor embodying my invention; Fig. 2 is a sectional perspective view of the cylinder block and moving parts of the compressor shown in Fig. 1 with the pump shaft withdrawn from the block; Fig. 3 is a sectional view along the line '33 of Fig. 2 with the piston turned to its extreme position; Fig. 4 is 'a view similar to Fig. 3 with the piston rotated 90; Fig. 5 is a perspective view of the oil pump structure shown in Fig. 1; and Fig. 6 is a sectional view on the line 66 of Fig. 3.

Referring to the drawing, in Fig. 1, I have shown a compression type refrigerating machine employing a compressor constructed in accord ance with my invention. Thisrefrigerating ma chine comprisesa motor 12 and a compressor 13. The motor and compressor are made as a unit and mounted on springs is within a sealed casing 15 to reduce noise. A condenser 16 in the form of a coiled tube is supported on radiating fins 17 secured to the casing 15, and the condenser communicates with the casing through a connection 15a. The compressor casing and condenser are mounted on a thermally insulated base 18 which forms the top of a refrigerator cabinet. and an evaporator comprising a header 19 and 8. depending wall 20 through which'refrigerant liquid circulates from the header is suspended below this top on legs 21. The header I9 is connected to receive liquid refrigerant from the condenser 16 through a flow controlling device 22 and conduit 23, and the header 19 is connected to the intake port of the compressor 13 through a conduit 24, which completes the refrigerant circuit.

The compressor 13, which embodies my invention, comprises a body 25 having a cylindrical bore 26 within which is mounted a rotary element 27, having a coaxial shaft extension 270 on which is mounted a rotor 28 of the motor 12. The body 25 is provided with bearings for the shaft of the compressor and the motor rotor 28. The construction of the compressor can best be seen in the perspective view shown in Fig. 2. The rotary element 2'! is provided with a transverse cylinder 29 within which is arranged a reciproeating piston or pumping element 30. The ends of the piston or displacement member 30 are made 'arcuate to conform to the sides of the bore 28 to provide a running fit between the cylinder walls and the piston at the end of each compression stroke, so that the clearance volume will be a minimum. In order to impart a reciproosting motion to the piston 30 when the rotary element 27 is rotated by the rotor 22, I provide a rotatable shaft 31 iournaled in thebodv 25' and having its axis arranged eccentric with respect to the 83518 of the shaft 27a. The shaft 31 is provided with a coaxial fiat lug 32 which slidably engages a transverse slot 33 in the piston 30. when the piston 30 is rotated by rotation of the rotary element 2'1, the lug 32v arranged in the transverse slot 33 on the piston causes the piston to reciprocate in the cylinder 29 as shafts 27a and 31are eccentrically Fig. 3 shows the reciprocating piston at the end of its compression stroke, and Fig. 4 shows the piston in its mid-position, the position of the lug 32 in. the slot 83 being shown in dotted lines. As the retsry element 27 is rotated clockwise from the position shown in Fig. 3 it will rotate the shaft 31 through the lug 32 and at the same time will slide the piston in the cylinder 29. when the rotary element has rotated through degrees the piston will be in the position shown in Fig. 4. In this position it will be noted that the piston 30 is midway between its extreme positions and that the lug 82 is now at the left side of the slot 38. when the piston has rotated through another 90 degrees it will be at the end of its stroke at the opposite end of the cylinder. It is thus seen that e. complete cycle is efl'ected every time the piston rotates through 180 degrees and consequently that, the compressor produces two compression strokes each revolution.

The compressor is provided with an intake port 84 in the form of a grooveextending about onefourth of the distance around the cylindrical bore 28, which communicates through a passage 36 and a check valve '37, with an intake pips coil 85 arrangedin-the casing 15 about the compressor to provide a flexible connection with the outlet pipe 24 of the evaporator. During the intake stroke the cylinder 29 is in communication with the intake port 34. Cut-off occurs when the piston 30 is in its extreme position away from the intake side of the wall 28. At the same time the other end of the piston 30 is in contact with the side of the cylinder 26 and is at the end of the exhaust stroke, the compressed gas having been forced out through an exhaust port 38. li'rcm this it is evident that there is practically no clearance loss in the compressor. When the compressor is stopped compressed fluid is prevented from returning to the intake line by the check valve 37 which is seated in an opening 39 by its own weight and the back pressure of the compressed fluid. The ends of the piston are alternately on. the high pressure and low pressure sides of the compressor, since gas is compressed by the piston alternately at each end thereof as the piston is rotated in the body 25.

At the bottom of the cylinder 25 is fitted a ring 40 which serves as a thrust bearing for the shaft 31 and also as a cylinder head for an oil or lubricant pump secured to the bottom of the shaft 31, and extends into the body of oil 40a as shown in Fig. 1. The ring 40 is provided with an opening 41 for admitting oil to the pump and a screen 42 secured by a plate 43 is provided :to prevent particles of solid matter from entering the pump. The. oil pump, as can best be seen by reference to Fig. 5, comprises a'cylindrical chamber 44 formed in the end of the block 25 and a blade 45 fitted in a transverse slot at the end of.

the shaft 31. An inlet port is provided in the form of the radial slot 46 in the shaft 31 on one side of the blade 45 and an exhaust port 47 opening on the other side of the blade 45 extends upward in the form of a groove through the shaft 31 to a chamber 48 in the rotary element 2'? below the piston 30. Lubricant is forced from the pump into the chamber 48 and thence around the piston 30 through an annular .groove 49 cut in the walls of the cylinder 29 and thence through a duct 50 to an annular channel 51 on top of the rotary element 2'7, which is partially covered by a plate 52 shown in Fig. l. The oil flows out around the shaft 27a of the motor 12 and also into a groove 53 in the rotary element 2'7 to lubricate the bearing surfaces of the rotary element. The oil is returned through a duct 54 to the bottom of the casing 15. This system of lubrication seals all parts of the compressor and minimlzes leakage.

In order to start the motor with low starting current, the compressor should not become loaded until after the motor has attained substantially full speed. To this end I provide an unloader comprising a by-pass between the ends of the piston 30, which is closed by pressure of the lubricating oil, which pressure is not built up until the motor has attained sufficient speed to properly carry the compressor load. In the particular construction illustrated, the by-pass is in the form of a longitudinal groove 55 in the walls of the cylinder 29, which is best seen in Fig. 6; however, this by-pass may be formed in any other suitable manner. When the motor 12 is first started the gas .or other'fiuid can pass freely from one end of the cylinder 30 to the other through the groove 55, which unloads the compressor. However, when the oil pump has built up sufllcient oil pressure and the annular groove.

49 is filled with oil, passage of gas through the groove 55 from one end of the piston to the other is prevented and the compressor is loaded. This result is accomplished by making the groove 55 of such small cross sectional area that the lubricantwill be effectively retarded from flowing therein because of high friction while the gas will flow readily when the oil pressure is low.

In the operation of the refrigerating machine shown, in Fig. 1, the level of the oil in the casing 15 is above the intake of the oil pump, and when the motor 12 is started, the rotor 28 will drive the rotary element 2'7 and the piston 30 will reciprocate in the cylinder 29. However, since the two ends of the piston are in communication through the groove 55 no appreciable load will be applied to the motor. As the shaft 31 is rotated oil pressure will be built up by the pump and the oil will flow out through the port 47, the chamber 48 and around the piston 30 to the annular groove 49 and into the by-pass groove 55 and will prevent further passage of gas from one end to the other of the cylinder 30. The pressure on the intake side of the compressor will then be decreased and the check valve 37 will open to admit refrigerant to the compressor. Refrigerant will then be supplied to the casing 15 under pressure through the exhaust port 38 of the compressor. The compressed refrigerant will fiow out of the casing 15 through the connection 15a into the condenser 16 where it will be liquefied and will then pass into the flow controlling device 22. The condensed liquid will be supplied by the flow controlling device 22 to the header 18 of the evaporator where it will accumulate and will be vaporized in the evaporator by the heat absorbed thereby. Vaporized refrigerant will return through the conduit 24 to the compressor 13, completing the refrigerant circuit. When the motor 12 comes to a stop, the oil pressure will be reduced so as to unload the compressor, and the compressed gas will pass back through the groove55 to the valve 37 which will be seated thereby to prevent back-flow of the compressed gas.

It is evident from the foregoing that I have provided a simple compressor construction, and an unloading mechanism therefor which is extremely simple and requires no separate unloading valve with moving parts.

Although I have shown my invention as embodied in a compressor applied to a refrigerating 115 machine, it is obvious that it may be useful for other purposes, and I do not, therefore, desire my invention to be limited to the particular arrangement shown and described, and I intend in the appended claims to cover all modifications 120 thereof which do not depart from the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A compressor having a body provided with 125 a chamber, means including a pumping element in the chamber in said body'for compressing a fluid, means including a passage communicating with the chamber in said body for unloading said compressor, and means for supplying a liquid 130 under pressure to said passage for loading said compressor.

2. A compressor having a body provided with a chamber having an inlet port and an outlet port, means including a passage communicating with the inlet port and the outlet port in the chamber in said body for unloading said compressor, and means for supplying a liquid under pressure to said passage for loading said compressor.

3. A compressor having a cylinder and a reciprocating piston arranged to compress fluid at both ends of said cylinder, means including a passage communicating with said cylinder at both ends of said piston for unloading said compressor, and means for supplying a liquid under pressure to said passage for loading said compressor.

4. A compressor including a cylinder and having a high pressure side and a low pressure side, a displacement member mounted in said cylinder 150 between the high and low pressure sides of said compressor, means for providing communication between the high pressure and the low pressure sides of said compressor, and means for forcing liquid under pressure into said communicating means and for preventing passage of compressed fluid. from the high pressure side of said compressor to the low pressure side thereof to had said compressor.

5. A compressor including a cylinder and having a high pressure side and a low pressure side,

a pumping element mounted in said cylinder be tween the high and low pressure sides of said compressor, means for providing communication between the high pressure and the low pressure sides of said compressor, means for driving said compressor, and means including a pump actuated by said driving means for forcing lubricantv under pressure into said communicating means and for preventing passage of compressed fluid from the high pressure side of said compressor to the low pressure side thereof to load said compressor.

6. A compressor including a body and having a high pressure side and a low pressure side, a rotary element having a transverse cylinder therein mounted in said body, a displacement member in the transverse cylinder in said rotary element, means for reciprocating said displacement member in said rotary element, means for providing communication between the high pressure side and the low pressure side of said compressor, and means for forcing lubricant under pressure into said communicating means and for preventing passage of compressed fluid from the high pressure side to the low pressure side of said compressor to load said compressor.

'7. A compressor including a body and having a high pressure side and a low pressure side, a-

rotary element having a transverse cylinder therein mounted in said body, a displacement member arranged in the transverse cylinder in said rotary element, means including a rotatable lug carried by said body and engaging said distending substantially the length of said walls and intersecting the annular groove therein, means for forcing lubricant under pressure around said piston, through the annular groove -in said walls ment, means for providing communication be= tween the ends of said piston, and means for forcing lubricant under pressure around said piston and into said communicating means and for preventing passage of compressed fluid from one end of said piston to the other end thereof to load said compressor.

10. A compressor including a body, a cylindrical rotary element 'mounted in said body and havsaid shaft slidably engaging said piston in the slot therein for reciprocating said piston in said rotary element and for driving said shaft, means providing communication between the ends'of said piston means including a pump driven by said shaft for forcing lubricant into said'compressor and into said communicating means and for preventing passage of compressed fluid from one end of said piston to the other end thereof to load said compressor.

11. A compressor including a body, a cylindrical rotary element mounted in said body, said body having cylindrical walls surrounding said element, a reciprocating piston mounted in said rotary element transversely of the axis thereof and s idable in said rotary element between extreme positions limited by contact with the wall of said body, the ends of said piston being shaped to conform to the cylindrical walls of said body, means for driving said rotary element, a rotatable shaft journaled in said cylinder eccentric with respect to said rotary element, and means including a lug on said shaft slidably engaging said piston for reciprocating said piston.

12. A compressor including a body, arotary element mounted insaid body, said rotary element having a cylinder therein arranged transversely of the axis thereof and a reciprocating piston in the transverse cylinder in said rotary element, said piston having a transverse slot therein intermediate the ends thereof, a rotatable lug mounted in said body eccentrically with respect to said rotary element and slidably engaging the transverse slot in said piston, means for providing communication between the opposite ends of said piston, and means for forcing lubricant under pressure in an annular stream around said piston tovcut oft communication between the ends of said piston to load said compressor.

13. A compressor including a body, a cylindrical rotary element mounted in said body, said cylinder having cylindrical walls surrounding said element'and in contact therewith, a reciproeating piston mounted in said rotary element" transversely of the axisthereof and slidable in said rotary element between extreme positions determined-by contact with said cylindrical walls,-

the ends of said pistoniconforming to said cylindrical walls and forming a running fit therewith when said piston is at the end of its range of movement; means for driving said rotary element,v

means for producing a reciprocating motion of said piston, means for providing communication v 

